Apparatus for testing extensible threads



June 5, 1934. R, LEE r AL 1,962,020

APPARATUS FOR TESTING EXTENSIBLE THREADS Filed Aug. 15, 1933 INVENTORS fOGEe/EEDEE/CALEE.

ATTORNEYS Patented June 5, 1934 UNITED STATES PATENT OFFICE APPARATUS FOR TESTING EXTENSIBLE THREADS Application August 15, 1933, Serial No. 685,212 In Great Britain June 28, 1932 9 Claims. (Cl. 7351) This invention concerns improvements in apparatus for testing threads composed wholly or partly of vulcanized rubber.

Such threads are highly extensible and elastic, these properties finding wide application for example in knitted goods for articles of clothing, wherein the thread is usually covered with one or more suitable textile windings.

It will be realized that it is of considerable importance to ensure that the threads which are incorporated into such fabrics, particularly when they are employed as covered threads,

have suflicient elasticity and textile strength to resist the stresses to which they are subjected in use for sport and/or other occasions since a breakage in the elastic core spoils the appearance of the article of which it forms a part and may also to a large extent nullify its close-fitting and supporting nature.

It has already been proposed to apply tension to artificial threads more particularly of cellulose and its derivatives for improving the physical characteristics of such thread, as for instance for the purpose of controlling the final cross section or for producing successive variation in cross section and also for increasing the tensile strength, lustre and resistance to heat-ed liquids.

It will be apparent that the purpose and effect of the present invention is directed, not towards imparting additional physical characteristics, but to testing existent characteristics, and in particular to testing the essential characteristics of extensibility in which it is essential to preserve an adequate and satisfactory standard in view of the nature of the articles made therefrom and in view of the varying conditions of flexure and stress which they will be called upon to undergo in use.

The invention is further characterized by incorporating in the apparatus means for producing a form of treatment of the elastic threads whereby the threads are given as it were a recuperative period during which the particles constituting the material of which they are composed are given an opportunity to recover from any fatigue due to the tensile test before being withdrawn to undergo any subsequent operation.

In order that the invention may be more easily understood and readily carried into effect, it will now be described with reference to the accompanying drawing, in which Fig. l is a diagrammatic perspective view of the apparatus; Fig. 2 is a diagrammatic side elevation of the apparatus shown in Fig. 1;

Fig. 3 is a perspective view of a roller showing the rubber coating.

Figs. 4 to- 8 inclusive, are diagrammatic side elevations of the apparatus showing difierent mechanisms for driving the two pairs of rollers at different speeds.

Figs. 9 and 10 show different modifications or means for pressing one roller of each pair resiliently against the other roller.

The elastic threads 1, which are to be subjected to test, are drawn between the fingers of a spacing comb 2 by means of which the threads may be separated to the required degree of spacing.

In the drawing, the test is shown, by way of example as applied to nine threads for the sake of clearness, but the number undergoing individual test simultaneously may be any convenient number according to the spacing between the threads and the output to be dealt with.

After passing through the upright fingers of the separating comb 2, the threads pass between the nip of a pair of rollers 3 and 4, the contacting surfaces of which are preferably coated with rubber to improve the grip of the thread as indicated in Fig. 3.

After being drawn through the first pair of rollers 3 and 4 at a speed determined by the surface velocity of the rollers, the threads are drawn into the nip of a second pair of rubber coated rollers 5 and 6, the surface speed of which is greater than that of the first pair of rollers.

The difference in surface speeds between the pairs of rollers may be obtained in several ways, by means such as belts 6a, pulleys 6b (Fig. 2), chains 60 (Fig. 4), or spur gearing 611 (Fig. 5).

For instance, a difierence in speed may be obtained by driving both pairs of rollers from. a common source, such as the motor 5a of Fig. 2, and driving the second roll from the first by a belt 6a.

In this case, as shown in Fig. 4, the diameter of the roller driven by the common belt or chain in the second pair of rollers 5 and 6 is of greater diameter than that driven in the first pair by the same belt or chain.

The rolls in each pair of rollers or the driven roller in each pair may, however, be of the same size and driven independently at predetermined speeds by motors 5b and 50, as shown in Fig. 8, through suitable chains or belts.

Thedifference in speed between the first and second pair of rollers causes the parallel threads between the pairs to be extended to a degree which is the same and which is dependent upon the ratio of the surface speeds which may be adjusted to produce the desired elongation by varying the drives or by the use of changewheels such as 6e and 61 (Figs. 6 and 7) or in any other convenient manner.

The pairs of rolls are preferably disposed one above the other with axes mutually parallel to one another and to a main conveyor '7 which is placed with one end beneath the second and lower of the two pairs.

This main conveyor '7 consists of an endless fabric belt carried on two rotating supports or rollers 8 and 9, one at each end, the conveying surface being driven at the same or at a lesser surface speed than the first pair of rollers.

The thread which has successfully passed the stretch test is thus collected by the main conveyor in a slack condition and is carried slowly towards the opposite end of the conveyor for further processing without being subjected to any tension, the threads being thus given a recuperative period in which they may freely contract to their initial unstretched condition which it is desirable they should resume before undergoing further operations.

The rolls 8 and 9 are preferably metallic or provided with metal surfaces so that any charges of electricity are conducted through the rolls and their bearings to earth.

To prevent those threads which do not pass the test and which break under the tensile stress exerted between the two pairs of traction elements from falling upon the main conveyor and becoming tangled with those lying coiled thereon, we interpose what may be conveniently described as a waste conveyor 10 which also serves to indicate and call the attention of the operative to material defective in tensile strength due to operation occurring at a previous stage in the process of manufacture.

The waste conveyor 10 is similar in construction to the conveyor 7, but unlike that conveyor, the upper surface of which is preferably level to eliminate any forces due to gravity, the waste conveyor is preferably inclined so that space is economized and waste or broken thread is led towards the ground where it may be received and removed in a suitable tray or other receptacle.

One end of the waste conveyor may be placed beneath thefirst pair of rollers in such a way that when a thread breaks between the rolls as for instance at 11, the free end of the broken thread contacts in its fall the surface of the waste conveyor which is driven in the opposite direction to that of the main conveyor and thus separates and carries the broken end away from the sound material, until such time as the causes of the breakage have been ascertained and removed, whereupon the fresh end can be reintroduced between the second pair of rollers for further test.

The rolls of the respective pairs are preferably pressed together by spring loading one roll of each pair by means of springs 69, as shown in Fig. 9, or by fluid pressure means 6?) as shown in Fig. 10.

It is also found advisable to use rubber coated rollers so that improved adhesion is obtained and the differential drag on the threads is positive and well defined in action between the respective mps.

Having now particularly described our said invention, we claim- 1. Apparatus for continuously testing the tensile strength of vulcanized rubber threads which comprises two spaced pairs of tractive rollers arranged to pass the thread first between the rollers of one pair and then between the rollers of the second pair and means to rotate the rollers of said second pair at a greater rate of speed than that of the rollers of said first pair, and an endless belt conveyor to receive threads passing through said second pair of rollers and means to move said conveyor at a less rate of speed than the surface speeds of said second pair of rollers.

2. Apparatus for continuously testing the tensile strength of vulcanized rubber threads which comprises two spaced pairs of tractive rollers arranged to pass the thread first between the rollers of one pair and then between the rollers of the second pair, means to rotate the rollers of said second pair at a greater rate of speed than that of the rollers of said first pair, and endless belt means for conveying threads from said second pair of rollers and means for conveying loose threads from said first pair of rollers separately from those of said second pair.

3. Apparatus according to claim 2, in which the two pairs of rollers and main conveyor are driven from a common drive.

4. Apparatus according to claim 2, in which the conveyor for removing loose threads is driven from a common drive.

5. Apparatus according to claim 2, in which the rollers are provided with a yielding surface.

6. Apparatus according to claim 2, in which the rollers of each pair are spring loaded one against the other.

7. Apparatus for continuously testing the strength of vulcanized rubber threads which comprises two spaced pairs of tractive rollers arranged to pass the threads first between the rollers of one pair and then between the rollers of the second pair, the rollers of said second pair being at a lower elevation than those of said first pair and being spaced backwardly from the direction of approach of said threads relative to said first pair of rollers, means to rotate the rollers of the first pair at one speed and the rollers of the second pair at a greater speed, endless belt conveyor means for conveying threads from the second pair of rollers, and separate conveyor means for conveying the loose threads and broken threads from said first pair of rollers before said threads reach said second pair of rollers.

8. Apparatus for continuously testing the tensile strength of filament material which comprises means for feeding said filament material at a predetermined uniform rate of speed, a second means for feeding said filament material passed thereto at a higher uniform rate of speed and contacting therewith so as to stretch said material and a continuous surface conveying means arranged to receive the filament material from said second means to carry said filaill) ment material at a rate of speed less than that of said second means to permit the filament material to contract from the stretched condition.

9. Apparatus for continuously testing the tensile strength of threads which comprises two spaced pairs of feeding means arranged to pass the thread first between the elements of one pair and then between the elements of the sec- 

